Monday, December 19, 2011

Productivity by Example: Liferay reverse-engineered

In this experiment, minuteproject demonstrates that it is possible to use Reverse-Engineering as a development methodology for Big Projects AND this from bootstrap time to the entire lifecycle of a Project.

To illustrate this postulat, I take enterprise-size opensource model (Liferay with150+ entities) upon which I apply minuteproject tracks.
It will quickly appear that performing 'bulk reverse-engineering' have strong limitations. Meanwhile by applying conventions deduced from the 'Reverse-Analysis' discipline, it will be possible to overcome them.
The generation will run releasing in couple of seconds (3 to 10) hundreds of artefacts.
Following Minuteproject philosophy, you'll will have to write 0 (Zero) LOC to get a working result and this can be achieved within 5 min-.
Eventually some code will be written on top and the result will be tested.
The technologies discussed will be:
  • JPA2 with Hibernate implementation
  • Querydsl
  • Ehcache 
  • Fitnesse
But other MP tracks can be applied.
The conclusion resumes the productivity benefit at project and enterprise level of embracing MinuteProject productivity philosophy.

Liferay
Liferay is an opensource portal, this article only focus on the database model.
Liferay Model
Setup 
The model is install on mysql database.
Now you can introspect your model.

Reverse-Analysis crash course
At first sight 150+ tables, 0 views.
Some tables start with QUARTZ, those are likely to be shipped with the Quartz scheduling framework, so they should be excluded from the generation.

At second sight (on mysql installation)
Entity with primary key but no foreign keys. => No relationships?
Mysql schema primary key are not autoincrement.

If reverse-engineering is performed as-is, then the bulk resulting artefacts in JPA2 will contain no relationships (no @OneToMany, @ManyToOne and @ManyToMany), so the resulting value will be quite poor (no graph navigation, query link to be done manually, no type safe benefit of Querydsl or Metamodel...)

Relation detection convention
Since the relationships are not formalised in terms of constraint, does it mean that there is none?
In fact, when having a deeper look inside the tables, some fields have name such as USER_ID and there is a strong chance that they are used for a relationship link with the User_ table primary key.
Let's assume it.
Since in minuteproject configuration the user can perform some enrichment and one of this enrichment consists in defining relationship, it is possible to enrich every table containing the field USER_ID by indicating it acts as a foreign key towards USER_ table.
// add snippet
It's fine, but it might be cumbersome since you'll have to do it more than 40 times and only for the 'towards User' relationships. What about the others?
A wiser way is to apply a convention:
What we need is to be able to detect relationships when those match a pattern.The pattern here is that the 'considered' foreign keys are fields ending with 'id' and whose beginning (column name without ending 'id') correspond to an existing table.
But this was not enough since some table ends with '_'.
So the convention has to take care of those exceptions and the match is done against the a map of those entity alias if the match was not successful via direct binding.
The final configuration of the convention is

<foreign-key-convention type="autodetect-foreign-key-based-on-similarity-and-map" 
column-ending="id" column-starting="" column-body="match-entity">
<property tag="map-entity" name="user_" value="user"/> 
<property tag="map-entity" name="group_" value="group"/>
<property tag="map-entity" name="organization_" value="organization"/>
<property tag="map-entity" name="permission_" value="permission"/>
</foreign-key-convention>

With this convention it is now possible to have 'virtual' foreign keys used by the generator to create @OneToMany, @ManyToOne and @ManyToMany relationships for JPA2 track.

Naming convention
The JEE conventions can be different from those retrieved from the Database structure:
Example: Some column ends with 'id' but in java we might not want that.
Here the convention for that
<column-naming-convention type="apply-strip-column-name-suffix" pattern-to-strip="ID" />

Collection naming convention
While reverse-engineering a problem is to give unambiguous names to list elements. Otherwise in java you have a compilation error. The safest way is to compose the name of this collection relationship (@OneToMany) with the name of the field holding the foreign key, and the name of entity having this FK. It get even worse when dealing with a many2many relationship where the intermediary link table as to be associated.
As a result, you can have very long name which is not quite handy.
Fortunately the convention apply-reference-alias-when-no-ambiguity is there for you!
<reference-naming-convention type="apply-referenced-alias-when-no-ambiguity" is-to-plurialize="true" />
It checks if while reducing the 'unambiguous' default name to 'just' the associated table (plurialize as option) there is no colision.
Remark
With conventions bear in mind that they are applied sequentially and so the order is very important!
Aliasing 
Entity name or column name can be aliased.
The alias will be used for the Java name but the ORM mapping will match the alias name to the correct entity name. 
Caching
To enable caching add a property to the target JPA2
               <property name="add-cache-implementation" value="ehcache"></property>
It is possible to associate caching to entities by two means:
By enrichment at entity level: Each entity marked as having their content-type="master-data" or ="reference-data" will have an associate cache entry
<entity name="country" content-type="reference-data"></entity>
By convention: describe a pattern of entity matching the requirement. Example all the entity ending with '_' could be considered as reference data
<entity-content-type-convention type="apply-content-type-to-entity-ending-with" pattern="_" content-type="reference-data"></entity-content-type-convention>
In this case the entity 'user', 'account', 'classname', 'contact', 'group', 'lock', 'organisation', 'permission', 'release', 'resouce' and 'role' will match the convention and thus have their cache entry in ehcache.xml
MinuteProject input
Input configuration
The analysis is resumed in the mp-config_LR.xml serving as input of MinuteProject
<!DOCTYPE root>
<generator-config>
    <configuration>
        <conventions>
            <target-convention type="enable-updatable-code-feature" />
        </conventions>       
        <model name="liferay" version="1.0" package-root="net.sf.mp.demo">
            <data-model>
                <driver name="mysql" version="5.1.16" groupId="mysql" artifactId="mysql-connector-java"></driver>
                <dataSource>
                    <driverClassName>org.gjt.mm.mysql.Driver</driverClassName>
                    <url>jdbc:mysql://127.0.0.1:3306/lportal</url>
                    <username>root</username>
                    <password>mysql</password>
                </dataSource>
                <primaryKeyPolicy oneGlobal="true">
                    <primaryKeyPolicyPattern name="none"></primaryKeyPolicyPattern>
                </primaryKeyPolicy>
            </data-model>
            <business-model>   
                    <generation-condition>
                    <condition type="exclude" startsWith="QUARTZ"></condition>
                    </generation-condition>
                <business-package default="liferay">
                    <condition type="package" startsWith="social" result="social"></condition>
                    <condition type="package" startsWith="user" result="user"></condition>
                    <condition type="package" startsWith="journal" result="journal"></condition>               
                </business-package>
                <enrichment>
                    <conventions>
                        <column-naming-convention type="apply-strip-column-name-suffix" pattern-to-strip="ID" />
                        <foreign-key-convention type="autodetect-foreign-key-based-on-similarity-and-map"
                            column-ending="id" column-starting="" column-body="match-entity">
                            <property tag="map-entity" name="user_" value="user"/>
                            <property tag="map-entity" name="group_" value="group"/>
                            <property tag="map-entity" name="organization_" value="organization"/>
                            <property tag="map-entity" name="permission_" value="permission"/>
                        </foreign-key-convention>
                        <reference-naming-convention type="apply-referenced-alias-when-no-ambiguity" is-to-plurialize="true" />       
                        <entity-content-type-convention type="apply-content-type-to-entity-ending-with" pattern="_" content-type="reference-data"></entity-content-type-convention>
                    </conventions>
                    <entity name="user_" alias="user"></entity>
                    <entity name="role_" alias="role"></entity>
                    <entity name="group_" alias="group"></entity>
                    <entity name="permission_" alias="permission"></entity>
                    <entity name="organization_" alias="organization"></entity>
                    <entity name="classname_" alias="classname"></entity>
                    <entity name="country" content-type="reference-data"></entity>
                </enrichment>
            </business-model>
        </model>
        <targets>
            <target refname="JPA2"
               fileName="mp-template-config-JPA2.xml"
               outputdir-root="../../dev/liferay/output/JPA2"
               templatedir-root="../../template/framework/jpa">
               <property name="add-querydsl" value="2.1.2"></property>
               <property name="add-jpa2-implementation" value="hibernate"></property>
               <property name="add-cache-implementation" value="ehcache"></property>
               
            </target>                        
            <target refname="LIB" fileName="mp-template-config-bsla-LIB-features.xml"
                templatedir-root="../../template/framework/bsla">
            </target>
    <target refname="CACHE-LIB" 
      fileName="mp-template-config-CACHE-LIB.xml" 
      templatedir-root="../../template/framework/cache">
    </target>            
        </targets>
    </configuration>
</generator-config>
Generation
Adapt the above config with the liferay database connection credentials.
You need version 0.7+ of minuteproject (and check that everything is fine by running the demos)
To generate place the following file mp-config_LR.xml into /mywork/config
Execute model-generation.(sh/cmd) mp-config_LR.xml

MinuteProject output
Generated artefacts
Entities
140+ entities have been created
12 Embeddable Id when composite primary have been found
Relationships
+- 300 OneToMany
+- 300 ManyToOne
+- 20 ManyToMany
Configuration
Entity Associate MetaModel for typesafe query
Maven pom.xml with querydsl integration
persistence.xml for test (local connection pool) and for release (jndi connection pool).
ehcache.xml

And All That in 10s less!
(local instance of mysql)


If you want to see what the resulting code looks like you can download on googlecode (version for minuteproject 0.8).
If you want to see what the Liferay datamodel looks like with relationships check here.


Test
But does it really work?
The sources are generated in /dev/liferay/output/JPA2
Writing a simple unit test in src/test/java which illustrates:
  • that you can write business added value
  • that querydsl for typesafe as an alternative to metamodel (MetaModel entities are also generated) is integrated
  • that ORM, ehcache configuration works
package my.liferay.test;

import java.util.List;

import javax.persistence.*;

import com.mysema.query.jpa.impl.JPAQuery;

import junit.framework.TestCase;
import net.sf.mp.demo.liferay.domain.liferay.Country;
import net.sf.mp.demo.liferay.domain.liferay.QCountry;

public class LiferayJPA2Test extends TestCase{
   
    public void testCountry() {
        // Initializes the Entity manager
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("liferay");
        EntityManager em = emf.createEntityManager();
        EntityTransaction tx = em.getTransaction();

        //use Query dsl for type safe query
        JPAQuery query = new JPAQuery(em);
        QCountry qcountry = QCountry.country;
        List l = query.from(qcountry)
           .where(qcountry.countryid.lt(0))
           .list(qcountry);
        //remove the countries
        for (Country country:l) {
         em.remove(country);
        }
        // create a country
        Country c = new Country();
        // no primary policy key given so associate one manually 
        c.setCountryid(new Long(-100));
        c.setName("NEW-country");
        c.setA2("A2");
        c.setA3("A3");
        c.setActive(new Short("1"));
        c.setNumber("5");

        tx.begin();
        em.persist(c);
        tx.commit();

        em.close();
        emf.close();   
    }
}

Running with maven
Execute mvn package
This will compile and test the code.
In the build, querydsl classes will be generated and compiled
In the test, at run time, ORM and ehcache configuration will be loaded.

The sql statement issue by Hibernate at the end of the test is 
Hibernate:
    insert
    into
        country
        (a2, a3, active_, idd_, name, number_, countryId)
    values
        (?, ?, ?, ?, ?, ?, ?)
So yes, it works!
And package liferayBackEnd-1.0-SNAPSHOT.jar is created.

But what happens if there is a compile time or runtime issue with the generated code?
Do not worry the generated code is updatable which means that you can patch the code but your modification will be kept over successive generations. More information at http://minuteproject.wikispaces.com/Updatable_Generated_Code

Extend
Here the reverse-engineering target just one type of target JPA2 track.
Extend with other MinuteProject tracks
Example:
FitNessize you development: Adding the following snippet into the 'targets' node of the main configuration will generate an entire Fitnesse wiki ready to use for your acceptance testing.
   <target refname="FitNesse" 
      name="default" 
      fileName="mp-template-config-fitnesse.xml" 
      outputdir-root="../../dev/liferay/output/FITNESSE"
      templatedir-root="../../template/framework/fitnesse">
   </target>
For more information see this article
Extend you model
Enrich you model with:
  • views
  • store procedure
  • constraints
Minuteproject will generate relevant artefacts for them.
Conclusions
This article shows how to set reverse-engineering approach as a fast development methodology.
It is far less intrusive and restricted than Domain Driven Development and much faster.
This article also insists on how to apply your own conventions via 'declarative conventions'.

Minuteproject unleashes your productivity!
Things and tedious tasks that where bound to stay for the lifetime of your project can be removed.
At this point it takes more time for a DBA to write and execute an alter statement than to have full backend synchronisation!
Now you can move agile on your backend development.

Conclusion for the LifeRay Dev team:
Altering your backend might be quite long if you want to go to JPA2 track described above. Meanwhile you can use MinuteProject without any intrusivity on other tracks.
MinuteProject FitNesse fixture generated for Liferay and this really help increasing QA!
Try other MinuteProject tracks: for example any DB query can be RESTified (fully REST app generated) within seconds...

More information
More information about Minuteproject 4 JPA2 track can be found here.

Thursday, December 15, 2011

Adding Ehcache to Openxava application

Introduction
This article shows how to quickly enable Ehcache on Openxava applications and thus improving performance.
When viewing an entity and its graph, relationships are loaded. Adding a second-level cache fasten the retrieval of associated elements, since already loaded elements are retrieved from cache and not database.
Eventually this page explains how minuteproject treats this aspect with keeping its promise: write nothing.
As an example, we will take the Lazuly minuteproject showcase.
Openxava-Ehcache integration
In Openxava, you describe your model in the manner of Java annotated POJO.The annotations come from the standard JPA2 ORM and Openxava specific ones.
But nothing prevents you to add others. This is what is done to add caching. There are also couple of configurations to undertake to enable caching.
List of actions
  1. Add ehcache.xml config file at the root of your sources
  2. Modify persistence.xml to include second level cache
  3. Add caching annotation (alongside JPA2)
Remark:
Openxava comes with the ehcache.jar so there is no need to add a dependency.
Detailed actions
Add ehcache.xml
In /persistence place ehcache.xml file
<ehcache>
    <defaultCache
            maxElementsInMemory="1000"
            eternal="false"
            timeToIdleSeconds="300"
            timeToLiveSeconds="300"
            overflowToDisk="false"
            diskPersistent="false"
            diskExpiryThreadIntervalSeconds="300"
            memoryStoreEvictionPolicy="LRU"
            />
   <cache
    name="your.domain.object"
    maxElementsInMemory="5000"
    eternal="false"
    timeToIdleSeconds="300"
    timeToLiveSeconds="600"
    overflowToDisk="false"
   />
</ehcache>
Modify persistence.xml
Persistence.xml file contains information related to the persitence unit such as connection pool info, class or configuration to load. 'persistence.xml' is located in /persistence/META-INF
We will append properties for L2 cache.
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
            <property name="hibernate.cache.provider_class" value="net.sf.ehcache.hibernate.SingletonEhCacheProvider" />
            <property name="net.sf.ehcache.configurationResourceName" value="/ehcache.xml" />
            <property name="hibernate.cache.use_query_cache" value="true" />
            <property name="hibernate.cache.use_second_level_cache" value="true" />
            <property name="hibernate.generate_statistics" value="true" />   

        </properties>
Add cache annotation
Here the hibernate annotation is used instead of the standard one (Cacheable in fact seems not to work)
Place Cache annotation at class level of your domain object.
@org.hibernate.annotations.Cache(usage = org.hibernate.annotations.CacheConcurrencyStrategy.READ_WRITE)
Example
Lazuly application
Lazuly is a sample database holding conference information used for MinuteProject showcase purpose.
Minuteproject generates a comprehensive set of artefacts to speedup the release of OX application.
Further information can be found in Minuteproject 4 Openxava Lazuly showcase.
On this part we focus on the artefacts generated for the caching specific.
Minuteproject for the generation base itself on a configuration file, where we define the datamodel to reverse engineer. In this configuration there is an enrichement part where you can add information.
One of this information deals with the type of content is held in an entity. There are 4 possibilities (reference-data, master-data, pseudo-static-data, live-business-data)
If you enrich your entity with the content-type="master-data" or "reference-data" MinuteProject 4 Openxava will generate associated caching.
This is done here for the entity Country.
     <entity name="COUNTRY" content-type="reference-data">
Here are the cache related artefacts

ehcache.xml
<ehcache>

  <!--
    Sets the path to the directory where cache files are created.

    If the path is a Java System Property it is replaced by its value in the
    running VM.

    The following properties are translated:
    * user.home - User's home directory
    * user.dir - User's current working directory
    * java.io.tmpdir - Default temp file path

    Subdirectories can be specified below the property e.g. java.io.tmpdir/one
    -->
<!--MP-MANAGED-UPDATABLE-BEGINNING-DISABLE @ehcache-main-config-conference@-->
    <diskStore path="java.io.tmpdir"/>

 <!--
    Mandatory Default Cache configuration. These settings will be applied to caches
    created programmtically using CacheManager.add(String cacheName)
    -->
    <defaultCache
            maxElementsInMemory="1000"
            eternal="false"
            timeToIdleSeconds="300"
            timeToLiveSeconds="300"
            overflowToDisk="false"
            diskPersistent="false"
            diskExpiryThreadIntervalSeconds="300"
            memoryStoreEvictionPolicy="LRU"
            />
<!-- The unnamed query cache -->
   <cache
    name="org.hibernate.cache.StandardQueryCache"
    maxElementsInMemory="1000"
    eternal="false"
    timeToLiveSeconds="300"
    overflowToDisk="false"
   />
<!--MP-MANAGED-UPDATABLE-ENDING-->

<!--MP-MANAGED-UPDATABLE-BEGINNING-DISABLE @cache-entity-country-conference@-->
   <cache
    name="net.sf.mp.demo.conference.domain.admin.Country"
    maxElementsInMemory="5000"
    eternal="false"
    timeToIdleSeconds="300"
    timeToLiveSeconds="600"
    overflowToDisk="false"
   />
<!--MP-MANAGED-UPDATABLE-ENDING-->

<!--MP-MANAGED-ADDED-AREA-BEGINNING @custom-cache-definition@-->
<!--MP-MANAGED-ADDED-AREA-ENDING @custom-cache-definition@-->

</ehcache>
Persistence.xml
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
             version="1.0">
             
    <!-- Tomcat + Hypersonic -->
    <persistence-unit name="default">
     <non-jta-data-source>java:comp/env/jdbc/conferenceDS</non-jta-data-source>
     <class>org.openxava.session.GalleryImage</class>
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
            <property name="hibernate.cache.provider_class" value="net.sf.ehcache.hibernate.SingletonEhCacheProvider" />
            <property name="net.sf.ehcache.configurationResourceName" value="/ehcache.xml" />
            <property name="hibernate.cache.use_query_cache" value="true" />
            <property name="hibernate.cache.use_second_level_cache" value="true" />
            <property name="hibernate.generate_statistics" value="true" />   
<!--MP-MANAGED-ADDED-AREA-BEGINNING @properties@-->
<!--MP-MANAGED-ADDED-AREA-ENDING @properties@-->
        </properties>
<!--MP-MANAGED-ADDED-AREA-BEGINNING @persistence-unit@-->
<!--MP-MANAGED-ADDED-AREA-ENDING @persistence-unit@-->
    </persistence-unit>       

<!--MP-MANAGED-ADDED-AREA-BEGINNING @persistence@-->
<!--MP-MANAGED-ADDED-AREA-ENDING @persistence@-->

</persistence>
Class annotation
@org.hibernate.annotations.Cache(usage = org.hibernate.annotations.CacheConcurrencyStrategy.READ_WRITE)
//MP-MANAGED-ADDED-AREA-BEGINNING @class-annotation@
//MP-MANAGED-ADDED-AREA-ENDING @class-annotation@
public class Country {

    @Hidden @Id @Column(name="id" )
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id; 
...
Generated code remark
The generated code has markers inside file extension comment.
Within MP-MANAGED-ADDED-AREA-BEGINNING and  MP-MANAGED-ADDED-AREA-ENDING you can place customized code
Within MP-MANAGED-UPDATABLE-BEGINNING-DISABLE and  MP-MANAGED-UPDATABLE-ENDING you can alter the code. To keep your modifications please change MP-MANAGED-UPDATABLE-BEGINNING-DISABLE into MP-MANAGED-UPDATABLE-BEGINNING-ENABLE.
Updatable code prevent you to lose your customisation over consecutive generations.
For more information on updatable code see Minuteproject updatable code.
Generation
  • Place the following file mp-config-LAZULY-OPENXAVA.xml in /mywork/config
  • on a prompt execute mp-model-generation(.sh/cmd) mp-config-LAZULY-OPENXAVA.xml 
  • the resulting artefacts in /DEV/output/openxava/conference 
To generate use the updated version of mp-config-LAZULY-OPENXAVA.xml
<!DOCTYPE root>
<generator-config>
 <configuration>
  <conventions>
   <target-convention type="enable-updatable-code-feature" />
  </conventions>  
  <model name="conference" version="1.0" package-root="net.sf.mp.demo">
   <data-model>
    <driver name="mysql" version="5.1.16" groupId="mysql" artifactId="mysql-connector-java"></driver>
    <dataSource>
     <driverClassName>org.gjt.mm.mysql.Driver</driverClassName>
     <url>jdbc:mysql://127.0.0.1:3306/conference</url>
     <username>root</username>
     <password>mysql</password>
    </dataSource>
    <!--
     for Oracle and DB2 please set the schema <schema> </schema>
    -->
    <primaryKeyPolicy oneGlobal="true">
     <primaryKeyPolicyPattern name="autoincrementPattern"></primaryKeyPolicyPattern>
    </primaryKeyPolicy>
   </data-model>
   <business-model>
    <!--
     <generation-condition> <condition type="exclude"
     startsWith="DUAL"></condition> </generation-condition>
    -->
    <business-package default="conference">
        <condition type="package" startsWith="STAT" result="statistics"></condition>
        <condition type="package" startsWith="COUNTRY" result="admin"></condition>
        <condition type="package" startsWith="ROLE" result="admin"></condition>    
    </business-package>
    <enrichment>
     <conventions>
      <column-naming-convention type="apply-strip-column-name-suffix"
       pattern-to-strip="_ID" />
      <reference-naming-convention
       type="apply-referenced-alias-when-no-ambiguity" is-to-plurialize="true" />
     </conventions>

     <entity name="COUNTRY" content-type="reference-data">
      <semantic-reference>
       <sql-path path="NAME" />
      </semantic-reference>
     </entity>
     <entity name="CONFERENCE_MEMBER">
      <semantic-reference>
       <sql-path path="FIRST_NAME" />
       <sql-path path="LAST_NAME" />
      </semantic-reference>
      <field name="STATUS">
       <property tag="checkconstraint" alias="conference_member_status">
        <property name="PENDING" value="PENDING" />
        <property name="ACTIVE" value="ACTIVE" />
       </property>
      </field>
      <field name="EMAIL">
       <stereotype stereotype="EMAIL" />
      </field>
     </entity>
     <entity name="SPEAKER">
      <field name="BIO">
       <stereotype stereotype="HTML_TEXT" />
      </field>
      <field name="PHOTO">
       <stereotype stereotype="PHOTO" />
      </field>
      <field name="WEB_SITE_URL">
       <stereotype stereotype="WEBURL" />
      </field>
     </entity>
     <entity name="PRESENTATION">
      <field name="STATUS">
       <property tag="checkconstraint" alias="presentation_status">
        <property name="PROPOSAL" value="PROPOSAL" />
        <property name="ACTIVE" value="ACTIVE" />
       </property>
      </field>
     </entity>
     <entity name="SPONSOR">
      <field name="STATUS">
       <property tag="checkconstraint" alias="sponsor_status">
        <property name="PENDING" value="PENDING" />
        <property name="ACTIVE" value="ACTIVE" />
       </property>
      </field>
      <field name="PRIVILEGE_TYPE">
       <property tag="checkconstraint" alias="sponsor_privilege">
        <property name="GOLDEN" value="Golden" />
        <property name="SILVER" value="Silver" />
        <property name="BRONZE" value="Bronze" />
       </property>
      </field>
     </entity>
     <!-- views -->
     <entity name="stat_mb_per_ctry_conf" alias="MEMBER_PER_COUNTRY_AND_CONFERENCE">
      <virtual-primary-key isRealPrimaryKey="true">
       <property name="virtualPrimaryKey" value="ID" />
      </virtual-primary-key>
     </entity>
     <entity name="stat_mb_by_role" alias="MEMBER_PER_ROLE_COUNTRY_AND_CONFERENCE">
      <virtual-primary-key isRealPrimaryKey="true">
       <property name="virtualPrimaryKey" value="id" />
      </virtual-primary-key>
      <field name="stat_mb_per_ctry_conf_ID" linkToTargetEntity="stat_mb_per_ctry_conf"
       linkToTargetField="id"></field>
     </entity>
    </enrichment>
   </business-model>
  </model>
  <targets>
   <!-- openxava -->
   <target refname="OpenXava" name="OpenXava"
    fileName="mp-template-config-openxava-last-features.xml"
    outputdir-root="../../DEV/output/openxava/conference"
    templatedir-root="../../template/framework/openxava">
   </target>

   <target refname="JPA2-LIB" fileName="mp-template-config-JPA2-LIB.xml"
    templatedir-root="../../template/framework/jpa">
   </target>
   
   <target refname="BSLA-LIB" fileName="mp-template-config-bsla-LIB-features.xml"
    templatedir-root="../../template/framework/bsla">
   </target>

   <target refname="CACHE-LIB" 
      fileName="mp-template-config-CACHE-LIB.xml" 
      templatedir-root="../../template/framework/cache">
   </target>
               
  </targets>
 </configuration>
</generator-config>

Test
To ensure that the caching is working properly:
  • Enable hibernate logging. Add the following snippet as extra properties in persistence.xml.
            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.format_sql" value="true" />
  • navigate to an entity that reference country (example Address)
  • When you view the detail of this entity you will notice that there is a load of the associated entity 'country'
  • But the second time you access to the details of this entity (or another entity referencing the same country instance), the country is not loaded twice from the database.